Process for agglomerating coal

ABSTRACT

A method of agglomerating coal particles, a portion of the coal particles having a fine particle size comprising (a) separating at least part of the coal particles having a fine particle size to provide a first fraction of coal particles having a reduced coal fines content; (b) contacting a slurry of coal particles of the first fraction with hydrocarbon oil to form coal-oil agglomerates; and (c) recovering coal-oil agglomerates of reduced oil content.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method of agglomerating coal particles withhydrocarbon oil, and more particularly to a method for reducing theamount of hydrocarbon oil required to form coal-hydrocarbon oilagglomerates.

2. Prior Art

Heretofore, it was known that coal particles could be agglomerated withhydrocarbon oils. For example, U.S. Pat. No. 3,856,668 to Shubert issuedDec. 24, 1974, and U.S. Pat. No. 3,665,066 to Capes et al. issued May25, 1972 disclose processes for recovering coal fines by agglomeratingthe fine coal particles with oil. U.S. Pat. No. 3,268,071 to Puddingtonet al. issued Aug. 23, 1966 and U.S. Pat. No. 4,033,729 issued July 5,1977 to Capes disclose processes for beneficating coal involvingagglomerating coal particles with oil in order to provide a separationof coal from ash. While these processes can provide some benefication ofcoal, improved ash and pyritic sulfur removals would be desirable.

The above U.S. Pat. No. 4,033,729 to Capes et al. relating to removinginorganic materials (ash) from coal significantly notes that pyriticsulfur has proven difficult to remove because of its possiblehydrophobic character. This disclosure confirms a long standing problem.The article "The Use of Oil in Cleaning Coal" Chemical and MetallurgicalEngineering, Vol. 25, pages 182-188 (1921) discusses in detail cleaningcoal by separating ash from coal in a process involving agitatingcoal-oil-water mixtures, but notes that pyrite is not readily removed insuch a process. In such a process, benefication of coal would be greatlyimproved if pyrite sulfur removal could be enhanced.

While it is known that hydrocarbon oil agglomeration can be useful inrecovering coal particles and/or beneficiating coal, the large amount ofhydrocarbon oil required in these prior art coal agglomeration processeshas detracted from their usefulness. It would be especially advantageousif the amount of hydrocarbon oil could be reduced in forming hydrocarbonoil coal agglomerates.

SUMMARY OF THE INVENTION

In its broad aspect, this invention provides a method for reducing theamount of hydrocarbon oil required for forming coal-oil agglomerates.The method involves agglomerating coal particles, a portion of the coalparticles having a fine particle size comprising:

(a) separating at least part of the coal particles having a fineparticle size to provide a first fraction of coal particles having areduced coal fines content;

(b) agitating a slurry of coal particles of the first fraction, waterand hydrocarbon oil to form coal-oil agglomerates; and

(c) recovering coal-oil agglomerates of reduced oil content.

This invention involves the discovery that the presence of even a smallamount of coal particles of a fine particle size increases the amount ofoil necessary to form coal-oil agglomerates. If these coal fines areremoved, coal-oil agglomerates reduced in oil content can be formed. Inanother aspect, it has also been discovered that the coal-oilagglomerates formed in this manner can accept coal fines formingcoal-oil agglomerates even further reduced in oil content. Thesecoal-oil agglomerates reduced in hydrocarbon oil content can have a sizesimilar to conventionally formed coal-oil agglomerates which require ahigher oil content.

In another aspect of this invention, a method for beneficiating coalinvolving this improved agglomeration process is presented.

In another aspect of the invention, a conditioning agent is employedwhich renders pyrite more amenable to separation on agglomerating coalparticles with hydrocarbon oil. In this aspect of the invention, animproved method for beneficiating coal is presented.

DETAILED DESCRIPTION OF THE INVENTION AND ITS PREFERRED EMBODIMENTS

In its broad aspect, this invention provides a method for reducing theamount of hydrocarbon oil required for forming coal-oil agglomerates. Apreferred method involves agglomerating coal particles, a portion of thecoal particles having a fine particle size comprising:

(a) separating at least part of the coal particles having a fineparticle size to provide (a) a first fraction of coal particles having areduced coal fines content, and (b) a second fraction of coal particleshaving a fine size;

(b) agitating a slurry of coal particles of the first fraction, waterand hydrocarbon oil to form coal-oil agglomerates;

(c) contacting an aqueous slurry of the coal-oil agglomerates with atleast part of coal particles from the second fraction; and

(d) recovering coal-oil agglomerates of reduced oil content.

This invention involves the discovery that the presence of even a smallamount of coal particles of a fine particle size very substantiallyincreases the amount of oil necessary to form coal-oil agglomerates. Ifthese coal fines are removed, coal-oil agglomerates reduced in oilcontent can be formed. It has also been discovered that the coal-oilagglomerates formed in this manner can accept coal fines thus formingcoal-oil agglomerates of even further reduced oil content.

Suitable coals which can be employed in the process of this inventioninclude brown coal, lignite, subbituminous, bituminous (high volatile,medium volatile, and low volatile), semi-anthracite, and anthracite. Inaddition, coal refuse from wash plants which have been used to upgraderun-of-mine coal can also be used as a source of coal. Typically, thecoal content of a refuse coal will be from about 25 to about 60% byweight of coal. Particularly preferred refuse coals are refuse from thewashing of metallurgical coals.

The coal particles employed in this invention can be provided by avariety of known processes, for example, grinding or crushing. A verysuitable coal particle size which is amenable to beneficiation andagglomeration is minus 24 mesh, for example, minus 24 mesh and 70% ormore on 300 mesh, preferably minus 50 mesh and 90% or more on 300 mesh.(Mesh sizes herein are based on U.S. Standard Screens.)

The known commercial processes for providing coal particles with sizescorresponding to these mesh sizes provide particles with a range ofvarious sizes.

In accordance with this invention, at least a portion of fine size coalparticles, i.e., especially those 50 microns and smaller are removedprior to agglomeration with oil. It is esepcially desirable to removeparticles in the "subsieve range", i.e., particles smaller than 37microns, which are small enough to pass the finest U.S. Standard Screen(400 mesh). It is especially preferred to remove greater than 50% of thevery fine particles, preferably greater than 80%, and even 90% or more.It is especially desirable to remove those particles smaller than 30microns, for example, particles having a size less than 20 microns andmore particularly less than 10 microns.

The coal fines can be separated from the coal particles using knownmethods, for example, elutriation or filtering an aqueous slurry of coalparticles. Generally, these coal fines comprise less than 10 percent, byweight, of the coal particles and more generally less 5 percent byweight. While it is preferable to remove almost all, or all, of the coalfines as set forth above, removal of a smaller portion can provide thebenefits of the invention, but to a lesser degree.

After the coal fines have been removed, the first fraction of coalreduced in coal fines is agglomerated with hydrocarbon oil to formcoal-oil agglomerates.

Coal-oil agglomerates can be readily formed by agitating a mixture ofwater, hydrocarbon oil and coal particles.

The water content of the mixture is not critical and can vary withinwide limits. Generally from about 30% to 95% water, and more preferablyfrom about 40% to 90% water, based on the weight of coal, will beemployed. There should be sufficient hydrocarbon oil present toagglomerate the coal particles. The optimum amount of hydrocarbon oilwill depend upon the particular hydrocarbon oil employed, the size ofthe coal particles, and the coal-oil agglomerate size desired.Generally, the amount of hydrocarbon oil initially employed will be fromabout 10% to 45%, often 15% to 30%, by weight, of coal.

The process can be suitably conducted at temperatures from ambient to200° F., for example from about 50° F. to 150° F., preferably 50° F. to100° F., and at pressures sufficient to maintain the liquid state ofliquids employed.

Suitable hydrocarbon oils for forming coal-oil agglomerates are derivedfrom petroleum, shale oil, tar sand and coil. Especially, suitablehydrocarbon oils are light and heavy refined petroleum fractions such aslight cycle oil, heavy cycle oil, heavy gas oil, clarified oil,kerosene, heavy vacuum gas oil, residual oils, coal tar and other coalderived oils. Mixtures of various hydrocarbon oils can be quitesuitable; particularly when one of the materials is very viscous.

The hydrocarbon oils are hydrophobic and will preferentially wet thehydrophobic coal particles. When the mixture of water, hydrocarbon oiland coal is agitated, the hydrocarbon oil wets (becomes associated with)the coal particles. These hydrocarbon wet coal particles will collidewith one another under suitable agitation forming coal-oil agglomerates.In general, the size of the coal-oil agglomerate is generally at leastabout 2 to 3 times, more generally at least 4 to 10 times, or largerthan the average size of the coal particles which make up the coal-oilagglomerates.

Agitating a mixture of water, hydrocarbon oil and coal particles to formcoal-oil agglomerates can be suitably accomplished using stirred tanks,ball mills or other apparatus. An apparatus which provides a zone ofshearing agitation is especially suitable for agitating the mixture.

When coal-oil agglomerates are formed in this manner, the coal particlesgenerally take up substantially all of the hydrocarbon oil presentforming coal-oil agglomerates of a size characteristic at the givenconditions and oil level employed. At a given coal particle size (andother conditions being equal), increasing the amount of oil providescoal-oil agglomerates of increased size.

In forming coal-oil agglomerates, a principal object is to form coal-oilagglomerates of a size such that the agglomerate can be readilyrecovered, i.e., preferentially separated from water and minerals (e.g.,ash and pyrite) associated with the coal. The desired size of theagglomerate can vary depending on the separation technique which isemployed. In order to conserve the valuable hydrocarbon oil, the amountof oil (and agglomerate size) should be as small as possible to providethe desired separation.

In accordance with this invention, reducing the coal fines content ofthe coal particles permits the formation of coal-oil agglomerates withless hydrocarbon oil than would be required to form similar sizeagglomerates if the fines content were not reduced.

After the coal particles reduced in fines content have been agglomeratedwith hydrocarbon oil, at least a portion, often all, of the separatedcoal fines can be added to an aqueous slurry of the coal-oilagglomerates and agitated to form coal-oil agglomerates further reducedin oil content. It has been found that the coal-oil agglomerates canaccept the additional coal fines without additional hydrocarbon oil. Thedesirable result is that coal-oil agglomerates even further reduced inoil content are formed.

If desired, coal fines from other sources can be added to the coal-oilagglomerates to form coal-oil agglomerates reduced in oil content. Theadded coal fines can be from about 1% to 20%. by weight, of the coal-oilagglomerates.

The resulting coil-oil agglomerates in the water slurry can be recoveredby separating, for example, by using suitable screens or filters. Thisseparation step also allows for removal of some of the mineral matter,for example, ash, such that the coal is beneficiated.

The recovered coal-oil agglomerates reduced in oil content will mostoften have from about 1% to 30%, preferably about 2% to 30% and morepreferably about 3% to 25% by weight of coal of hydrocarbon oil. Mostgenerally, recovered coal-oil agglomerates reduced in oil content willhave from about 3% to 10%, by weight of coal, hydrocarbon oil.

The process of forming coal-oil agglomerates reduced in oil content canbe used to recover aqueous slurries of coal particles, and can also beemployed to beneficiate coal.

A preferred method of beneficiating coal containing ash and iron pyritemineral matter in accordance with this invention, involves the followingsteps:

(1) reducing the coal size to form coal particles, and separating atleast part of the coal particles having a fine particle size to provide(a) a first fraction of coal particles having a reduced coal finescontent, and (b) a second fraction of coal particles having a fine size;

(2) contacting an aqueous slurry of the coal particles of reduced sizefrom step 1, or as fractions (a) and (b) with a promoting amount of atleast one conditioning agent capable of modifying or altering theexisting surface characteristics of the pyrite under conditions toeffectuate alteration or modification of at least a portion of thecontained pyrite;

(3) contacting the slurry of coal particles of the first fraction withhydrocarbon oil to form coal-oil agglomerates;

(4) contacting the aqueous slurry of the coal-oil agglomerates with atleast part of the coal particles from the second fraction; and

(5) recovering coal-oil agglomerates wherein the coal reduced ironpyrite and mineral content.

In this preferred aspect of the invention, the coal particles containingash and iron pyrite mineral matter are contacted with at least oneconditioning agent which renders pyrite more amenable to separation fromthe coal particles on forming coal-oil agglomerates. In this aspect ofthe invention, coal particles are contacted with a promoting amount ofat least one conditioning agent capable of modifying or altering theexisting surface characteristics of the pyrite under conditions toeffectuate alteration or modification of at least a portion of thecontained pyritic sulfur. This altered or modified pyritic sulfur ispreferentially rejected to the aqueous phase. The result is that whenthe coal particles are agglomerated with hydrocarbon oil and recoveredcoal-oil agglomerates are coal-oil agglomerates wherein the coalexhibits reduced sulfur and ash content. Another advantage of thisbeneficiating process is that high levels of hydrocarbon oil are notneeded.

An amount of conditioning agent is employed which promotes theseparation of pyrite from coal. Generally, from about 0.1% to 15%,preferably from about 0.5% to 5%, by weight of coal, of conditioningagent is employed.

Preferably the amount of conditioning agent is based on the ash contentof the coal. From about 0.05% to 30%, preferably 0.05% to 10%, and mostpreferably from about 1% to 10%, by weight, ash is employed.

Preferably, the coal is contacted with the conditioning agent in aqueousmedium. The contacting is carried out at a temperature such to modify oralter the pyrite surface characteristics. For example, temperatures inthe range of about 0° C. to 100° C. can be employed, preferably fromabout 50° C. to about 100° C., and still more preferably from about 20°C. to about 35° C., i.e., ambient conditions. Temperatures above 100° C.can be employed, but are not generally preferred since a pressurizedvessel would be acquired. Temperatures in excess of 100° C. andpressures above atmospheric, generally pressures of from about 5 psig toabout 500 psig, can be employed, however, and can even be preferred whena processing advantage is obtained. Elevated temperatures can also beuseful if the viscosity and/or pour point of the agglomerating oilemployed is too high at ambient temperatures to selectively agglomeratecoal as opposed to ash and pyrites.

Examples of useful conditioning agents include inorganic compounds whichcan hydrolyze in water, preferably under the conditions of use, and thehydrolyzed forms of such inorganic compounds, preferably, such formswhich exist in effective amounts under the condition of use. Proper pHand temperature are necessary for some inorganic compounds to exist inhydrolyzed form. When this is the case, such proper conditions areemployed. The inorganic compounds which are hydrolyzed or exist inhydrolyzed form under the given conditions of contacting (e.g.,temperature and pH) can modify or alter the existing surfacecharacteristics of the pyrite. Preferred inorganic compounds are thosewhich hydrolyze to form high surface area inorganic gels in water, suchas from about 5 square meters per gram to about 1000 square meters pergram.

Examples of such conditioning agents are the following:

I. Metal Oxides and Hydroxides having the formula:

M_(a) O_(b).xH₂ O and M(OH).xH₂ O, wherein M is Al, Fe, Co, Ni, Zn, Ti,Cr, Mn, Mg, Pb, Ca, Ba, In or Sb; a, b and c are whole numbers dependingon the ionic valence of M, and x is from 0 to about 3.

Preferably M is a metal selected from the group consisting of Al, Fe,Mg, Ca and Ba. These metal oxides and hydroxides are known materials.Particularly preferred are aluminum hydroxide gels in water at pH 7 to7.5. Such compounds can be readily formed by mixing aqueous solutions ofwater soluble aluminum compounds, for example, aluminum nitrate oraluminum acetate, with suitable hydroxides, for example, ammoniumhydroxide. In addition, a suitable conditioning agent is formed byhydrolyzing bauxite (Al₂ O₃.xH₂ O) in alkaline medium to an alumina gel.Calcium hydroxide represents another preferred conditioning agent.Calcined calcium and magnesium oxides are also preferred conditioningagents. Mixtures of such compounds can very suitably be employed. Thecompounds are preferably suitably hydrolyzed prior to contacting withcoal particles in accordance with the invention.

II. Metal aluminates having the formula:

M'_(d) (AlO₃)_(e) or M'_(f) (AlO₂)_(g), wherein M' is Fe, Co, Ca, Mg,Ba, Ni, Pb or Mo; and d, e, f, and g are whole numbers depending on theionic valence of M.

Compounds wherein M' is Ca or Mg, i.e., calcium aluminates and magnesiumaluminates are preferred. These preferred compounds can be readilyformed by mixing aqueous solutions of water soluble calcium andmagnesium compounds, for example, calcium or magnesium acetate withsodium aluminate. Mixtures of metal aluminates can very suitably beemployed. The compounds are most suitably hydrolyzed prior to contactingwith coal particles in accordance with the invention.

III. Aluminasilicates having the formula:

Al₂ O₃.×SiO₂ wherein x is from about 0.5 to 5.

A preferred aluminasilicate conditioning agent for use herein has theformula Al₂ O₃.4SiO₂. Suitably aluminasilicates for use herein can beformed by mixing together in aqueous solution a water soluble aluminumcompound, for example, aluminum acetate, and a suitable alkali metalsilicate, for example, sodium metasilicate, preferably, in suitablestoichiometric amounts to provide preferred compounds set forth above.

IV. Metal silicates wherein the metal is calcium, magnesium, tin, bariumor iron.

Metal silicates can be complex mixtures of compounds containing one ormore of the above mentioned metals. Such mixtures can be quite suitablefor use as conditioning agents.

Calcium and magnesium silicates are among the preferred conditioningagents of this invention.

These conditioning agents can be prepared by mixing appropriate watersoluble metal materials and alkali metal silicates together in anaqueous medium. For example, calcium and magnesium silicates, which areamong the preferred conditioning agents, can be prepared by adding awater soluble calcium and/or magnesium salt to an aqueous solution ordispersion of alkali metal silicate.

SUitable alkali metal silicates which can be used for forming thepreferred conditioning agents are potassium silicates and sodiumsilicates. Alkali metal silicates for forming preferred calcium andmagnesium conditioning agents for use herein are compounds having SiO₂:M₂ O formula weight ratios up to 4:1, wherein M represents an alkalimetal, for example, K or Na.

Alkali metal silicate products having silica-to alkali weight ratios(SiO₂ :M₂ O) up to about 2 are water soluble, whereas those in which theratio is above about 2.5 exhibit less water solubility, but can bedissolved by steam under pressure to provide viscous aqueous solutionsor dispersions.

The alkali metal silicates for forming preferred conditioning agents arethe readily available potassium and sodium silicates having an SiO₂ :M₂O formula weight ratios up to 2:1. Examples of specific alkali metalsilicates are anhydrous Na₂ SiO₃ (sodium metasilicate), Na₂ Si₂ O₅(sodium disilicate), Na₄ SiO₄ (sodium orthosilicate), Na₆ Si₂ O₇ (sodiumpyrosilicate) and hydrates, for example, Na₂ SiO₃. nH₂ O (n=5, 6, 8 and9), Na₂ Si₄ O₉.7H₂ O and Na₃ HSiO₄.5H₂ O. Examples of suitable watersoluble calcium and magnesium salts are calcium nitrate, calciumhydroxide and magnesium nitrate. The calcium and magnesium salts whenmixed with alkali metal silicates described hereinbefore form verysuitable conditioning agents for use herein.

Calcium silicates which hydrolyze to form tobermorite gels areespecially preferred conditioning agents for use in the process of theinvention.

V. Inorganic Cement Materials

Inorganic cement materials are among the preferred conditioning agentsof the invention. As used herein, cement material means an inorganicsubstance capable of developing adhesive and cohesive properties suchthat the material can become attached to mineral matter. Cementmaterials can be discrete chemical compounds, but most often are complexmixtures of compounds. The most preferred cements (and fortunately, themost readily available cements) are those cements capable of beinghydrolyzed under ambient conditions which are the preferred conditionsof contacting with the coal in the process.

These preferred cement materials are inorganic materials which whenmixed with a ratio of water to form a paste can set and harden. Cementand materials used to form cements are discussed in Kirk-Othmer,Encyclopedia of Chemical Technology, 2D. Ed., Vol. 4 c. 1964 by JohnWiley & Sons, Inc., Pages 684 to 710 being incorporated by referenceherein. Examples of cement materials include calcium silicates, calciumaluminates, calcined limestone and gypsum. Especially preferred examplesof cement materials are the materials employed in hydraulic limes,natural cement, masonry cement, pozzolan cement and portland cement.Such materials will often include magnesium cations in addition tocalcium.

Commercial cement materials, which are very suitable for use herein, aregenerally formed by sintering calcium carbonate (as limestone), orcalcium carbonate (as limestone) with aluminum silicates (as clay orshale). Preferably, such materials are hydrolyzed prior to use asconditioning agents.

With some coals, the material matter associated with the coal may besuch that on treatment under proper conditions of temperature and pH themineral matter can be modified in situ to provide the suitablehydrolyzed inorganic conditioning agents for carrying out the process.In such cases, additional conditioning agents may or may not be requireddepending on whether an effective amount of conditioning agent isgenerated in situ.

The conditioning agents suitable for use herein can be employed alone orin combination.

The coal particles are preferably contacted with the conditioning agentin an aqueous medium by forming a mixture of the coal particles,conditioning agent and water, and the conditioned coal particles aresubsequently agglomerated with oil in accordance with this invention.

Suitable conditioning agents are disclosed in U.S. Patent ApplicationSer. No. 944,452, filed Sept. 21, 1978 commonly assigned, the entirecontent being incorporated by reference herein.

The coal-oil agglomerates of the invention reduced in oil content, andpreferentially beneficiated can be recovered in a variety of ways.

Preferably the recovery is a separation effected by taking advantage ofthe size difference between coal-oil agglomerates and unagglomeratedmineral matter. For example, the coal-oil agglomerates can be separatedfrom the water and liberated ash and pyrite, etc., by filtering with barsieves or screens, which predominately retain the coal-oil agglomerates,but pass water and unagglomerated mineral matter. When this technique isemployed, coal-oil agglomerates of a size suitable for ready filteringshould be formed.

Often it is desired to use small amounts of oil to form coal-oilagglomerates. Small amounts of oil, however, provide small coal-oilagglomerates. Small coal-oil agglomerates (aggregates and flocs) can bemore desirably separated by taking advantage of the different surfacecharacteristics of the coal-oil agglomerates, and ash and conditionedpyrite, for example, employing well known froth flotation and/orskimming techniques.

The process of this invention provides coal-oil agglomerates reduced inhydrocarbon oil content which are suitable for separation using any ofthese techniques. The desirable result is that reduced amounts ofhydrocarbon oil can be employed in beneficiating coal.

While this invention has been described with respect to various specificexamples and embodiments, it is to be understood that the invention isnot limited thereto and that it can be variously practiced within thescope of the following claims.

What is claimed is:
 1. A method of agglomerating coal particles, aportion of the coal particles having a fine particle size comprising:(1)separating at least part of the coal particles having a fine particlesize to provide a first fraction of coal particles having a reduced coalfines content; (2) contacting a slurry of coal particles of the firstfraction with hydrocarbon oil to form coal-oil agglomerates; and (3)recovering coal-oil agglomerates of reduced oil content.
 2. The methodof claim 1 wherein the coal particle size is minus 24 mesh and at lest90% on 300 mesh.
 3. The method of claim 1 wherein the hydrocarbon oil isselected from the group consisting of light cycle oil, heavy cycle oil,heavy gas oil, clarified oil, kerosene, heavy vacuum gas oil, residualoils, coal tar and other coal derived oils.
 4. The method of claim 3wherein the recovered coal-oil agglomerates reduced in oil content havefrom about 1% to 30% by weight coal of hydrocarbon oil.
 5. A method ofagglomerating coil particles, a portion of the coal particles having afine particle size comprising:(1) separating at least part of the coalparticles having a fine particle size to provide (a) a first fraction ofcoal particles having a reduced coal fines content, and (b) a secondfraction of coal particles having a fine size; (2) agitating a slurry ofcoal particles of the first fraction, water and hydrocarbon oil to formcoal-oil agglomerates; (3) contacting an aqueous slurry of the coal-oilagglomerates with at least part of the coal particles from the secondfraction; and (4) recovering coal-oil agglomerates of reduced oilcontent.
 6. The method of claim 5 wherein the coal particle size isminus 24 mesh and at least 90% on 300 mesh.
 7. The method of claim 6wherein the hydrocarbon oil is selected from the group consisting oflight cycle oil, heavy cycle oil, heavy gas oil, clarified oil,kerosene, heavy vacuum gas oil, residual oils, coal tar and other coalderived oils.
 8. The method of claim 7 wherein the recovered coal-oilagglomerates reduced in oil content have from about 3% to 25% by weightcoal of hydrocarbon oil.
 9. The method of claim 5 wherein the coalparticles having a fine particle size are smaller than 50 microns. 10.The method of claim 5 wherein the coal particles having a fine particlesize are smaller than 30 microns.
 11. A method of beneficiating coalcontaining ash and iron pyrite mineral matter comprising:(1) reducingthe coal size to form coal particles, and separating at least part ofthe coal particles having a fine particle size to provide (a) a firstfraction of coal particles having a reduced coal fines content, and (b)a second fraction of coal particles having a fine size; (2) contactingan aqueous slurry of the coal particles of reduced size from step 1 oras fractions (a) and (b) with a promoting amount of at least oneconditioning agent capable of modifying or altering the existing surfacecharacteristics of the pyrite under conditions to effectuate alterationor modification of at least a portion of the contained pyrite, (3)contacting the slurry of coal particles of the first fraction withhydrocarbon oil to form coal-oil agglomerates; (4) contacting theaqueous slurry of the coal-oil agglomerates with at least part of thecoal particles from the second fraction; and (5) recovering coal-oilagglomerates wherein the coal reduced iron pyrite and mineral content.12. The method of claim 11 wherein the coal particle size is minus 24mesh and at least 90% on 300 mesh.
 13. The method of claim 12 whereinthe hydrocarbon oil is selected from the group consisting of light cycleoil, heavy cycle oil, heavy gas oil, clarified oil, kerosene, heavyvacuum gas oil, residual oils, coal tar and other coal derived oils. 14.The method of claim 13 wherein the recovered coal-oil agglomeratesreduced in oil content have from about 3% to 25% by weight coal ofhydrocarbon coil.
 15. The method of claim 11 wherein the coal particleshaving a fine particle size are smaller than 50 microns.